A conventional technique of using a multi-layer graphene sheet for a wiring is known. A graphene sheet is used for a wiring and it is thereby possible to obtain a wiring with ideal resistance by using ballistic conductivity of the graphene.
When a graphene sheet is used for a wiring, a wiring structure different from a conventional structure of a Cu wiring is required. For example, in a wiring body described in JP-A 2009-70911, a TiN electrode film is provided as a junction of a wiring with a contact plug. Therefore, a graphene sheet of each layer is connected to the contact plug through the TiN electrode film, and functions as a current path in the wiring.
However, according to the wiring body described in JP-A 2009-70911, since the wiring and the contact plug are indirectly connected through the TiN electrode film, there is a problem that a configuration of a connecting portion of the wiring with the contact plug is complicated. Therefore, there is a possibility that electrical resistance increases due to poor connection at the connecting portion, in addition to this, there is a problem that the number of processes is increased in order to form the TiN electrode film.